/*
 * Copyright (c) 2022 Huawei Device Co., Ltd.
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
export default abstract class LiteralCoder {
    private lc: number;
    private literalPosMask: number;

    constructor(lc: number, lp: number) {
        this.lc = lc;
        this.literalPosMask = (1 << lp) - 1;
    }

    getSubcoderIndex(prevByte: number, pos: number): number {
        let low: number = prevByte >> (8 - this.lc);
        let high: number = (pos & this.literalPosMask) << this.lc;
        return low + high;
    }
}